Editing of man/mhical.man.
Editing of man/mhical.man.

- Don't use capitalised .SH, when uncapitalised .SS will do
- Remove some early .SH/.SS to improve narrative
- Delete superfluous .fi

It could be argued that each of the (now) .SSs, which have been
demoted from .SHs, are unnecessary or, at least, not in line with
the other man pages . Demotion may suffice, for now.

mcr/nmh,mcr/nmh